| 摘要 |
<p>PURPOSE:To inexpensive recover an Na compound in refining slag at high purity with high efficiency by making soluble impurities in a slurry contg. Na2O extracted from the slag slightly soluble, removing them, crystallizing Na2O, and returning filtrate after the crystallization to the extracting vessel. CONSTITUTION:Refining slag 1 contg. an alkali metallic compound is pulverized and fed to an extracting vessel 2 to extract an Na2O component with an extracting soln. having >=4 apparent water ratio, and the prepared slurry 5 is fed to an impurity removing vessel 6. In the vessel 6 it is reacted with an impurity remover 8 made of the calcined product of dolomite or dolomitic limestone, hydroxide thereof, or lime to make P, S and Si of soluble impurities slightly soluble. This slurry 10 is fed to a filter 11 to discharge residue 13, part of the filtrate 14 is used as a refluxing soln. 15, and the remainder is fed to a crystallizing vessel 17 through a cooler 14. In the vessel 17 Na2O is crystallized, and the Na2O crystallized slurry 20 is fed to a filter 21 to recover the Na2O 23. The filtrate is returned to the vessel 2 as a circulating soln. 24 together with the soln. 15.</p> |
